Method of concentrating nitric acid.



No. 854,928. 4 PATENTED MAI 28, 1907.

' E. GOLLETT.

METHOD OF GONCBNTRATING NITRIC AGID..

APPLIOATION FILED AUG. 10.1905.

Unrrn sTATnsr 'rE 'r orrron.

EMIL COLL ET T, OF OHRISTIANIA, NORWAY.

Specification of Letters Patent.

METHOD oF CONCENTRATING NITRIC ACID.

PatentedMay 28, 1907.

Application filed Auzust 10, 1905. ,Serial No. 273,618-

To all whom it may concern:

' Be it known that I, EMIL COLLETT, a subject of the Kingdom of Norway, residing at Christiania, Norway, have invented certain new and useful Improvements 1n Methods of Concentrating l\1tr1c Ac1d; and I do hereby declare the following to be a full, clear, and

acid of 40%, by which one part of acid is mixec with three or four parts of concentrated snlluric acid and then distilled, is combmed with great costs on the inalntenance of expensive apparatus; besides this it requires too. great a quantity of fuel, as ivell for the concentration of the nitric acid as especiall for the concentration of the sulfuric acii, which was diluted by this process. Consequently efl'orts have already for a long time been made to produce new and more economical means of the concentration.

I have now succeeded in.,linding a method by which the concentration of the acid may be carried out with far less expenses, than by the methods earlier known. Bv thls method the concentration is effected by an air-or gas current, which by aid of suitable apparatus is brought into an intimate contact with the acid, so that the water contained therein is evaporated. F or this purpose the acid is preferably led into a non-corrosive vessel, which is thus arranged, that the hot airor gascurrent passes the surface of the acid and partly is forced into Hereby the water contained in the acid.

is evaporated. Some of the acid itself, is, however, also evaporated, and in order to regain this acid there is, above the noncorrosive vessel, placed a column apparatus of non-corrosive matcrial, which is fed from above with the diluted nitric acid. Here the hot vapors and air from the vessel containin the acid are forced through the diluted and cold acid, which is [lowing in, whereby the acid vapors are condcnscd and the diluted acid exposed to a previous heating and partly also to a com-cntration. After their passage through the column apparatus the vapors quired as a distillate. passes through a vessel filled with bits of continue their way through a coolingtube or serpent, whereby some diluted acidis ac Then the air current non-corrosive material, where most of the acid contained 111 the va ors is retained. If

at last the air currentis ed through a vessel filled with limestone and lime, any loss of acid may be avoided, the nitric aicid combin mg with the lime to calcium nitrate, which may be utilized. In this way the chief quantity of nitric acid about 60%, while the distillate containing about 10% of the original quantity of nitric acid may be profitably utilized.

will be concentrated up to The annexed drawmg is a diagrammatic view of a preferablearrangement of apparatus for carrying out the above described process. I

a is the non-corrosive vessel, in which the concentration of the acid is effected by aid, of the hot air-or gascurrent, which is led in at b and by suitably arranged walls is driven 'forward and backward over the surfacetof the acid and then passes out through the column apparatus 0 arranged above the concentration vessel. Theair current is then led on through the cooling apparatus (1, where the greater part of the vapor and the acid contained in the same is concentrated; then it passes through a tower 0, filled with pieces of non-corrosive material, as for in.,

stance, coke, cl-lainottestone, etc, and at lastthrough the tower f, which is filled with limestone and lime.

Claims. l. The method of concentrating nitric acid which includes exposing the dilute acid to the influence of a current of a hot gaseous medium free from acid and bringing the so obtained mixture of gases and vapors'into contact with a cold aqueous liquid for the purpose of condensing the vapors.

2. The method of concentrating nitric acid, which includes exposing the dilute acid to the influence of a current of a hot gaseous medium free from acid, and bringing the soobtained mixture of gasesand vapors into contact with a cold stream of diluted nitric acid for the purpose of condensing the major part of the vapors and Ipre-heatmg the diluted nitric acid.

3. The method of concentrating nitric acid, which includes exposing the acid to the influence of a current of a hot gaseous medium, bringing the so obtained mixture of gases and vapors into contact with a cold stream of diluted nitric acid for the purpose of condensing the major portion of the vapors and preheating the diluted nitric acid,

, and bringing the mixture of gases and vapors into contact with cold bodies for condensation of a further quantity of nitric acid vapors.

. 4. The method of concentrating nitric acid, which'includes exposing the acid to the influence of a current of a hot gaseous medium, bringing the resulting mix. are of gases and vapors into contact with a cold stream of diluted nitric acid to mndense the major part of the vapors and preheat the diluted nitric acid, then bringing the mixture of gases and vapors into contact with cold bodies to condense a further quantity of acid, and finally into contact with a substance capable of forming .a nitrate with nitric acid.

5. The method of concentrating nitric acid, which consists in exposing the acid to the influence of hot air, bringing the resulting mixture of gases andvapors into contact with cold diluted nitric acid to condense the in ajnr.

portion of the vapors and preheat the diluted acid, then bringing the mixture of gas and vapors into contact with cold surfaces to condense a further quantity of acid and finally into contact with limestone.

in testimony that I claim the foregoing as my invention, I have signed my name in presence of two subscribin r witnesses.

E IL COLLETT.

Witnesses Jon. Rns, CHR. Email. 

